In a blog about the "unscheduled" update, Oracle says it has changed Java's default security settings to "high" which it says means users will be notified of any extra applications which start running while they are browsing.

Oracle says the vulnerability applies to the latest version of the software, Java 7. It has declined to comment.

Java is a programming language that enables software to run on many operating systems. It is also installable on web browsers.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.